Interactions

Interactions with Drugs

Cigarette smoking decreases serum concentrations of beta-carotene and other carotenoids and depletes body stores of beta-carotene. However, oral beta-carotene supplementation should not be recommended in smokers because supplemental beta-carotene in certain doses is associated with a significantly higher risk of lung and prostate cancer in smokers. Smokers and people with a history of asbestos exposure should avoid taking beta-carotene supplements.

Cholestyramine (Questran®) and colestipol (Colestid®) can reduce the absorption of fat-soluble vitamins, including beta-carotene. Serum levels of beta-carotene can be reduced, but this is probably only in proportion to the lowering of cholesterol (on which beta-carotene is transported). Supplements are not usually necessary.

Colchicine can cause disruption of intestinal mucosal function, resulting in malabsorption of beta-carotene.

Oral neomycin sulfate can reduce beta-carotene absorption, but short-term use is unlikely to have a significant effect.

Orlistat (Xenical®) can decrease the absorption of beta-carotene and other fat-soluble vitamins. It is recommended that patients take a multivitamin supplement, and separate the dosing time by at least two hours from orlistat.

Interactions with Herbs and Dietary Supplements

Consumption of a natural carotenoid mixture has been shown to lower the increase in oxidative stress induced by the fish oil. This carotenoid mixture may also enhance the plasma triglyceride-lowering effect of the fish oil.

Iron supplementation in infants with marginal vitamin A status has led to lower plasma vitamin A concentrations and greater vitamin A liver stores. Some researchers recommend that iron supplementation in infants should be accompanied by measures to improve vitamin A status.

Beta-carotene supplementation has been shown to lower serum lutein concentrations. Lutein from food sources does not seem to result in the decrease in beta-carotene concentrations that accompanies administration of lutein supplements.

Plant sterols have been shown to reduce beta-carotene bioavailability in some studies and not to have a significant effect in others. The effects on cholesterol levels are also unproven.

Supplementation of beta-carotene may decrease the vitamin E concentration in tissues.